Depression has been defined using many words over time but is currently called Major Depressive Disorder (MDD). It has also been referred to as clinical depression, major depression, unipolar depression, recurrent depression, and in the early 20th century was known as melancholy. Depression is classified as a mood disorder and is characterized as a cluster of symptoms, (syndrome) that includes low mood, low self-esteem, lack of interest in anything usually pleasurable, (anhedonia), and in general, a feeling of lethargy and low energy. Major depressive disorder has an often disabling effect on a person’s life with trouble sleeping, working, eating, and impairs life to a large extent. But, as in the case of anxiety, depression occurs along a continuum, from simply “feeling down” to totally disabling. And, although anyone can have a low day with no clinical significance, someone who has MDD has a difficult time negotiating life. The following vignette may help to illustrate the complexities of depression: I first met Ann, a 35 year old woman, when I became her case manager as she was seeking continued treatment after a long problem with major depression. She had been hospitalized for 3 months but was doing well with medication and therapy. My task was to support her at home with paperwork, and personal organization of her day to day life. She lived in a very rural location but had a car and a part-time job and was managing her illness with excellent results. My home visits were generally every two weeks, and she also met with me when receiving therapy in our office setting. For the first six months, all went very well; her apartment was always clean, she dressed appropriately, was consistent with her medication and therapy, and kept appointments as scheduled. Upon arrival for a usual scheduled home visit, there was no answer at the door, but her car was in the usual parking space. I called her on the cell phone several times and received no answer. Her landlady lived in an adjacent apartment and I asked her if she had seen Ann but was advised that it had been two or three days since she had been seen going to work. I called the office to determine if she had called to cancel the appointment but that had not happened. I then spoke to her psychiatrist and he suggested that I have the landlady open the door and make a visual check. And, this is the difficult choice as I have no intention of invading individual privacy, but concern for Ann’s safety was the determining factor. The landlady and I entered the apartment as I knew immediately that there was a problem. The apartment was a mess and the heat was off. With reluctance, the landlady accompanied me to the bedroom and we found Ann barely conscious and in extreme distress. An ambulance was called and she was transported to a local hospital where life-saving efforts were performed. Ann had taken most of her medication in an attempt to commit suicide but had failed to understand that the medications were not lethal. But the attempt raises many questions. Most importantly, what causes a person who is managing her illness so well to resort to a suicide attempt? Despite what we do know about MDD we still do not know what triggers the desire to give up on mental health management. We do know that there is an interplay between the biology of the brain and the environmental issues. But, we have no way of knowing what was in Ann’s mind when the decision was made. I spoke to her in the hospital and she cannot explain what happened. We are aware that between 3 and 4 % of patients with MDD do commit suicide, and that some 60% of all suicides have some mood disorder associated with them. Ann continues to be in treatment but will have to struggle with the symptoms for a long time to come.